English verb conjugation
COULD SAP

Regular verb: sap - sapped - sapped

Affirmation

Simple form	V-ing form
I could sap you could sap he could sap we could sap you could sap they could sap	I could be sapping you could be sapping he could be sapping we could be sapping you could be sapping they could be sapping
Perfect	V-ing perfect
I could have sapped you could have sapped he could have sapped we could have sapped you could have sapped they could have sapped	I could have been sapping you could have been sapping he could have been sapping we could have been sapping you could have been sapping they could have been sapping

Negation

Simple form	V-ing form
I could not sap you could not sap he could not sap we could not sap you could not sap they could not sap	I could not be sapping you could not be sapping he could not be sapping we could not be sapping you could not be sapping they could not be sapping
Perfect	V-ing perfect
I could not have sapped you could not have sapped he could not have sapped we could not have sapped you could not have sapped they could not have sapped	I could not have been sapping you could not have been sapping he could not have been sapping we could not have been sapping you could not have been sapping they could not have been sapping

Interrogative form

Simple form	V-ing form
could I sap? could you sap? could he sap? could we sap? could you sap? could they sap?	could I be sapping? could you be sapping? could he be sapping? could we be sapping? could you be sapping? could they be sapping?
Perfect	V-ing perfect
could I have sapped? could you have sapped? could he have sapped? could we have sapped? could you have sapped? could they have sapped?	could I have been sapping? could you have been sapping? could he have been sapping? could we have been sapping? could you have been sapping? could they have been sapping?

Interro-negative form

Simple form	V-ing form
could I not sap? could you not sap? could he not sap? could we not sap? could you not sap? could they not sap?	could I not be sapping? could you not be sapping? could he not be sapping? could we not be sapping? could you not be sapping? could they not be sapping?
Perfect	V-ing perfect
could I not have sapped? could you not have sapped? could he not have sapped? could we not have sapped? could you not have sapped? could they not have sapped?	could I not have been sapping? could you not have been sapping? could he not have been sapping? could we not have been sapping? could you not have been sapping? could they not have been sapping?